From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparing different types of ventilation systems, including those used on railway coaches.
| Identifier | ExFiles\Box 117\4\ scan0121 | |
| Date | 20th February 1941 | |
| To Rm.{William Robotham - Chief Engineer} From Rs{Sir Henry Royce's Secretary}/EAG. 1021 Rs{Sir Henry Royce's Secretary}/EAG.6/ET.20.2.41. V E N T I L A T I O N. Regarding ventilating systems used on railway coaches, we have contacted the Chief of the L.M. & S. Coach Drawing Office, and discussed with him the various types of ventilators they fit, and which they have found to be the most satisfactory on their saloons and passenger cars. The latest and most satisfactory type, which they are now fitting, is in the form of two glass sliding panels carried in metal frames and situated in an aperture above the main windows, as photographs Type 1, attached. The two panels are of equal size, and they are fitted with deflectors to the two vertical edges which abut when closed. The deflectors are on the outside, so that when the sliding panels are opened a certain distance and the train is in motion, an extracting effect takes place. When the sliding panels are fully opened, the effect is reversed. Previous to fitting the above, a louvre type ventilator was fitted, as photographs type 2, the construction of which was in the form of vertical glass slats in a frame, and linked together. These were operated by a handle, so that they could be set to extract or inject air. When the ventilator was not in use, the aperture was closed by a hinged or sliding window. The ventilating effect of both is similar, the difference between them being that the type now used is cheaper to produce and lighter in weight. Comparing the two types mentioned, with the pivoting window which we are using, the principle and effect are similar. With the pivoting window open and the sliding window behind it closed, air is extracted from the body of the car. If the sliding window is lowered into the door, the reverse is obtained and air is forced in. The difference between the latest railway type and ours is that the railway types have permanent deflectors fitted (which would be noisy) and the air flow is controlled by the size of the gap between the edges of the sliding glass panels. With our type, the rear edge of the pivoting window swings outwards and acts as a deflector, the flow of air from inside the car being controlled by the amount that it is opened. With a strong side wind, it appears that the railway type would not be so satisfactory as the type we are fitting, the reason being that the opening between the sliding panels is approximately parallel. | ||